RFID tags are used to associate an object with information stored in the tag such as an identification code. The RFID tag is read via the principle of electromagnetic (EM) communication wherein an interrogator containing a transmitter generates an EM signal that is transmitted via an antenna associated with the interrogator to an antenna associated with the tag. In a passive tag the antenna receives a portion of the transmitted energy and through a rectifier generates DC power for operating a reply generation circuit. The reply generation circuit encodes the information stored in the tag into an EM reply signal that is radiated by the antenna. The radiated signal is received by the interrogator antenna and the information is decoded by the interrogator.
A typical RFID tag module has a limited read range that may be less than 40 cm. To enhance performance of the tag when it is applied to an object it is known to couple a secondary or auxiliary antenna to the antenna on the tag. The auxiliary antenna may be larger than the tag antenna and may be located on the same object in close proximity to the tag antenna so that it is electromagnetically coupled thereto.
Prior art methods for manufacturing such range enhancing or auxiliary antennas include etching of suitable conductors such as copper or aluminum on a substrate, and/or depositing conductive ink by means of screen printing, photographic or offset printing processes or the like. However, such manufacturing methods require too many steps and are relatively slow and expensive to apply. They are also not able to be incorporated into a cardboard roll manufacturing process.